A range detection device that detects which range is selected in a gear position of an automatic transmission is conventionally known. In such a range detection device, a position of a movable member which moves with a member that switches the gear position of the automatic transmission is detected so that a shift range selected by a vehicle occupant is detected, for example. As a method for detecting the position of the movable member, a contact-type method for detecting the position of the movable member by contacting the movable member with a detection portion, and a noncontact-type method for detecting the position of the movable member without contacting the movable member with a detection portion are known. U.S. Pat. No. 4,022,078 discloses a noncontact-type range detection device. In the range detection device, a magnetic detection element of the detection portion detects magnetism of a magnet arranged on the movable member so that the position of the movable member is detected.
In contrast, JP-A-2009-68535 discloses a noncontact-type range detection device that is placed inside an automatic transmission in the state of oil immersion. In the range detection device, in order to prevent a magnetic detection element and a substrate, to which electronic components such as the magnetic detection element are installed, from being exposed to oil (hereinafter referred to as AT hydraulic oil), the magnetic detection element and the substrate are covered with a sealing member.
However, in manufacturing processes of the range detection device of JP-A-2009-68535, if there is a small gap between the substrate and the magnetic detection element, the gap is not filled with the sealing member, and the sealing member may be hardened with air bubbles existing between the substrate and the magnetic detection element. In the case where air bubbles exist between the substrate and the magnetic detection element, if a temperature of an installation environment of the range detection device is increased, the air bubbles expand and stress is applied to the magnetic detection element, and thereby a magnetic detection property of the magnetic detection element may change. Moreover, if the air bubbles between the substrate and the magnetic detection element expand too much, stress may concentrate at a solder connection portion between the substrate and the magnetic detection element and the solder connection portion may be destroyed. Further, a position of the magnetic detection element with respect to the substrate may change. In this manner, if the property and the position of the magnetic detection element change, detection accuracy of the position of the movable member by the magnetic detection element, that is, detection accuracy of the range of the automatic transmission may be decreased.
By performing degassing treatment such as vacuuming before the sealing member is hardened, the air bubbles between the substrate and the magnetic detection element can be removed to some extent. However, it is difficult to remove the air bubbles thoroughly. Moreover, if such degassing treatment is performed, cost of equipment may be increased and the manufacturing processes may become complicated, thereby increasing manufacturing cost.